Former pirate radio DJs from illegal 1960s stations are now broadcasting legally across the airwaves from off the Essex coast.

More than a dozen DJs have boarded the LV18, a former lightship moored half a mile off Harwich.

"Pirate BBC Essex", involving BBC Radio 2's Johnnie Walker, marks 40 years since many pirate stations went off air under the Marine Offences Act.

BBC Essex presenters will join the station for its six-day run.

Johnnie Walker said: "It is just to pay homage and respect to these times.

Maybe younger people who have heard some vague thing about a pirate station on a ship will listen and think I like that

Johnnie Walker

"For the people who were there listening, to be able to listen to it again, they will love it and they will certainly love all the music.

"Maybe younger people who have heard some vague thing about a pirate station on a ship will listen and think, 'I like that'."

Pirate radio stations were popular in the 1960s as the music they played was largely not catered for elsewhere. By mooring off the coast the pirate stations could evade broadcasting authorities.

The pirate stations transformed the radio industry and many of Radio Caroline's DJs went to broadcast legally on the BBC's new pop music service, Radio 1.

BBC Radio 2's Walker says listerners will love the music

Canadian Gordy Cruse, a former Radio Caroline DJ, said: "The fan mail was just phenomenal. We would come ashore after a two-week stint for a week off and there would be a crowd of young ladies waiting to see the DJs."

The DJs on board the LV18, who include Ed Stewart and Emperor Rosko, will be "hot bedding" - sleeping in rotation according to their presenting shift - just as they did in the 1960s.

But 40 years on the technology has changed, and the service is now available to listeners across the world.

Pirate BBC Essex is on 729, 765 and 1530 medium wave and at bbc.co.uk/essex.

An exhibition including Radio Caroline memorabilia will be held at the Ha'penny Pier, Harwich, while the station is broadcasting.